Control device having an integral reflecting structure for a sensing circuit

ABSTRACT

A wall-mounted keypad may include a light detector circuit located inside the keypad that is configured to measure an ambient light level in a space. The light detector circuit may receive ambient light through an aperture that is hidden from view by the keypad. The keypad may include a reflector for directing ambient light onto the light detector circuit. The keypad may include an enclosure that houses the light detector circuit. The enclosure may define a recess that exposes at least a portion of the light detector circuit. The enclosure may include a reflector that may focus ambient light received through the aperture onto the light detector circuit. The keypad may include a control circuit that may be configured to illuminate the indicia of respective buttons of the control device in response to actuations of the one or more buttons, in accordance with the measured ambient light level.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/174,545, filed Oct. 30, 2018, which is a continuation of U.S. patentapplication Ser. No. 15/583,819, filed May 1, 2017, now issued as U.S.Pat. No. 10,129,951 on Nov. 13, 2018, which is a continuation of U.S.patent application Ser. No. 15/165,559, filed May 26, 2016, now issuedas U.S. Pat. No. 9,717,130 on Jul. 25, 2017, which claims priority toU.S. provisional patent application No. 62/166,219, filed May 26, 2015,both of which are incorporated herein by reference in their respectiveentireties.

BACKGROUND

Home automation systems, which have become increasing popular, may beused by homeowners to integrate and control multiple electrical and/orelectronic devices in their homes. For example, a homeowner may connectappliances, lights, blinds, thermostats, cable or satellite boxes,security systems, telecommunication systems, and the like to each othervia a wireless network.

The homeowner may control such connected devices using, for instance, acentral controller, a dedicated remote control device such as awall-mounted keypad, a user interface provided via a phone, tablet,computer, or other device that is directly connected to a home networkor remotely connected via the Internet, or the like. Connected devicesmay be configured to communicate with each other and/or with a controldevice, for example to improve their efficiency, convenience, and/ortheir usability.

However, known dedicated remote control devices, such as wall-mountedkeypads, for example, typically exhibit one or more undesirablecharacteristics. For example, in known wall-mounted keypads that arebacklit it may be difficult for a user to distinguish an activelyselected button from an adjacent unselected button due to ambient lightin a space where the keypad is installed. In other known wall-mountedkeypads, the lens of a light detector that measures ambient light may beinstalled on a faceplate of the keypad. However, such a solution may beaesthetically unpleasing.

SUMMARY

As described herein, a control device that is configured as awall-mounted keypad may include a light detector circuit that is locatedin an interior of the control device and that is configured to measure alight level of ambient light in a space in which the keypad isinstalled. The light detector circuit may be, for example, a photodiode.The keypad may define an aperture through which the ambient light may bereceived at the light detector circuit. The aperture may be hidden fromview by one or more components of the keypad. The keypad may include areflector for directing the light received through the aperture onto thelight detector circuit.

The keypad may include a faceplate and an adapter that is configured tobe mounted to a structure. The faceplate and the adapter may beconfigured to be removably attached to one another. The adapter mayinclude a lower wall that defines the aperture. The keypad may includean enclosure that houses the light detector circuit. The enclosure maybe attached to an inner surface of the faceplate. The enclosure maydefine a recess that exposes at least a portion of the light detectorcircuit. The enclosure may include a reflector that may focus ambientlight received through the aperture on the light detector circuit. Thereflector may include a reflective surface that is configured to directambient light onto a light-receiving surface of the light detectorcircuit. The reflective surface may operate as a parabolic reflector.

The keypad may include one or more buttons having indicia that areindicative of functions performed by the keypad in response to actuationof the buttons. The indicia may be configured to be illuminated from aninterior of the keypad. The keypad may include one or more light sourcesthat are configured to illuminate the buttons. The keypad may include acontrol circuit that may be configured to control the one or more lightsources to illuminate indicia of respective buttons in response toactuations of one or more buttons, in accordance with the ambient lightlevel measured by the light detector circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front-facing perspective view of an example control device,configured as a wall-mounted keypad, for use in a load control systemfor controlling the amount of power delivered to one or more electricalloads.

FIG. 2 is a rear-facing perspective view of the example control deviceillustrated in FIG. 1, with a faceplate component of the control deviceattached to an adapter component of the control device.

FIG. 3 is rear-facing exploded rear view of the example control deviceillustrated in FIG. 1, with the faceplate detached from the adapter.

FIG. 4 is a rear view of the example control device illustrated in FIG.1.

FIG. 5 is a bottom view of the example control device illustrated inFIG. 1.

FIG. 6 is a side section view of the example control device illustratedin FIG. 1.

FIG. 7 is an enlarged portion of the section view illustrated in FIG. 6.

FIG. 8A is a front-facing exploded view of another adapter to which thefaceplate of the example control device illustrated in FIG. 1 may beattached.

FIG. 8B is a rear-facing exploded view of the adapter illustrated inFIG. 8A.

FIG. 9 is a simplified block diagram of electrical components of theexample control device illustrated in FIG. 1.

FIG. 10 is a graph that illustrates an example active adjustment curvefor adjusting a duty cycle of current conducted through a light-emittingdiode behind an active button of a control device in response to ameasured ambient light level.

FIG. 11 is a graph that illustrates an example active adjustment curvefor adjusting a duty cycle of current conducted through a light-emittingdiode behind an inactive button of a control device in response to ameasured ambient light level.

FIG. 12 depicts an example backlighting process that may be implementedin the example control device illustrated in FIG. 1.

DETAILED DESCRIPTION

FIGS. 1-5 depict an example control device that is configured for use ina load control system for controlling one or more load control devices,such as dimming modules, and/or one or more electrical loads, such aslighting loads, motorized window treatments, or the like. As shown, theexample control device is configured as a wall-mounted keypad 100. Thekeypad 100 may include a faceplate 102 and an adapter 108. The faceplate102 and the adapter 108 may be configured to be removably attachable toeach other (e.g., as shown in FIGS. 2 and 3). The faceplate 102 and theadapter 108 may together be referred to as a faceplate assembly. Thefaceplate 102 and the adapter 108 may be made of any suitable material,and may be made of the same or different materials. For example, thefaceplate 102 and the adapter 108 may be made of plastic.

The keypad 100 may further include one or more buttons 104, such as theillustrated four buttons 104. The faceplate 102 may define an opening106 that extends therethrough and that is configured to at leastpartially receive the buttons 104. The faceplate 102 and the buttons 104may have respective metallic surfaces. The adapter 108 may be configuredto be mounted to a structure, such as a structure within an interiorwall of a building. The illustrated keypad 100 may be configured tocontrol a load control device, such as a load control device configuredto control an amount of power delivered to one or more electrical loads(e.g., one or more lighting loads) from a power source (e.g., analternating-current (AC) power source).

The keypad 100 may be configured to transmit one or more digitalmessages to one or more external load control devices via acommunication link. The digital messages may, for example, comprisecommands that cause the external load control devices to controlcorresponding electrical loads. The communication link may comprise awired communication link or a wireless communication link, such as aradio-frequency (RF) communication link. Alternatively, the keypad 100may comprise an internal load control circuit for controlling the powerdelivered to one or more electrical loads. Examples of load controlsystems having remote control devices, such as the keypad 100, aredescribed in greater detail in commonly-assigned U.S. Pat. No.6,803,728, issued Oct. 12, 2004, entitled “System For Control OfDevices,” and U.S. Patent Application Publication No. 2014/0001977,published Jan. 2, 2014, entitled “Load Control System HavingIndependently-Controlled Units Responsive To A Broadcast Controller,”the entire disclosures of which are incorporated herein by reference.

Each button 104 may have a body that may be made of a translucent (e.g.,transparent, clear, and/or diffusive) material, such as plastic, and mayfurther have a metallic outer surface. For example, each button 104 mayhave a translucent plastic body (not shown) and a veneer made of anopaque material, such as a metallic sheet (not shown), that may beadhered to a front surface of the body of the button 104.

The buttons 104 may include indicia 120, such as text, icons, or thelike (e.g., as shown in FIG. 1). The indicia 120 may be cut through theveneer of the buttons 104, for example using a laser cutting process, amachining process, photo-etching, or another metal-removal process. Theindicia 120 may be filled, for instance with a translucent or clearmaterial. Alternatively, the indicia 120 may be etched into surfaces(e.g., outer surfaces and/or inner surfaces) of the respective buttons104, may be printed on the outer surfaces of the buttons 104, or may beotherwise formed or displayed on the buttons 104. The indicia 120 may beindicative of respective functions that are invoked by depressing thecorresponding buttons 104 of the keypad 100, for example causing thekeypad 100 to transmit a command to an associated load control devicethat causes the load control device to adjust a corresponding lightingload in accordance with a preset, such as a lighting scene.

Alternatively, the buttons 104 may be coated with another type of opaquematerial, such as paint, and the indicia 120 may be etched into theopaque material. In addition, the bodies of the buttons 104 mayalternatively be made of another type of translucent material, such asglass. An opaque material, such as paint, may be coated onto respectiverear surfaces of the bodies of the buttons 104 and the indicia 120 maybe etched into the opaque material.

The buttons 104 may be backlit to allow the indicia 120 to be read in awide range of ambient light levels. The buttons 104 may be illuminatedby one or more light sources, such as light emitting diodes (LEDs) thatare located inside an interior of the keypad 100, for instance behindand/or to the side of each button 104. Illumination from the LEDs mayshine through the translucent body, but not through the metallic sheet,such that the indicia 120 of each button 104 is illuminated.

The keypad 100 may operate to backlight the buttons 104, such that theindicia 120 of a button 104 that is associated with a selected preset(e.g., an “active” preset) is illuminated to an active surfaceillumination intensity L_(SUR1), and the indicia 120 of remainingbuttons 104 of the keypad that may be associated with other presets(e.g., “inactive” presets) are illuminated to an inactive surfaceillumination intensity L_(SUR2). The active surface illuminationintensity L_(SUR1) may be greater than the inactive surface illuminationintensity L_(SUR2), such that a user of the keypad 100 may identifywhich of the presets is selected based upon the intensity of theillumination of the indicia 120 of the buttons 104 of the keypad 100.Alternatively, the faceplate 102 of the keypad 100 may include a body(not shown), for instance made of plastic, and a metallic veneer withindicia cut therethrough that is attached to the body and that may beilluminated by the LEDs (e.g., backlit).

The keypad 100 may include an enclosure 130 that is configured to housea printed circuit board (PCB) 132 on which the electrical circuitry ofthe keypad 100 may be mounted. The enclosure 130 may be configured to bemechanically attached to the faceplate 102, for instance using screws131, such that the buttons 104 may be received in the opening 106 of thefaceplate 102. The adapter 108 may be configured to be mounted to astructure, for instance via mounting screws (not shown) received throughmounting openings 133. As shown, the adapter 108 may include an upperwall 134, a lower wall 136, and opposed side walls 135 that extend fromthe upper wall 134 to the lower wall 136. The upper wall 134, side walls135, and lower wall 136 may be referred to as outer walls of the adapter108, and may define a perimeter of the adapter 108. Respective surfacesof the upper wall 134, side walls 135, and lower wall 136 may beconfigured to abut an outer surface of the structure when the adapter108 is mounted to the structure.

The faceplate 102 and the adapter 108 may be configured to be removablyattached to each other. For example, as shown the faceplate 102 maysnap-fit connectors 137 and the adapter 108 may define recesses 109 thatmay each be configured to receive and engage with a corresponding one ofthe snap-fit connectors 137. The adapter 108 may define an opening 138that extends therethrough and that is configured to at least partiallyreceive the enclosure 130 when the faceplate 102 is attached to theadapter 108. The keypad 100 may further include an electrical connector139 which may electrically connect circuitry on the PCB 132 to a powersource, such as an external direct-current (DC) power source, and/or mayconnect the keypad to 100 a communication link, such as a wiredcommunication link.

An ambient light level, for example in a space (e.g., a room) in whichthe keypad 100 is installed, may affect the ability of a user of thekeypad 100 to read the indicia 120 on the buttons 104. For example, ifthe contrast between the brightness of the illuminated indicia 120 of abutton 104 and the brightness of an adjacent surface of the button 104is too low, the illuminated indicia 120 may appear washed out to theuser. Accordingly, the keypad 100 may include an ambient light detectioncircuit having a photodiode 140 (or an integrated circuit having aphotodiode), which may be mounted to the PCB 132, for instance to a rearsurface of the PCB 132, and may be configured to measure a light levelof the ambient light in the space. The photodiode 140 may be configuredto receive light through a light receiving surface that extends parallelto the rear surface of the PCB 132. As shown, the enclosure 130 maydefine a recess 142 that may be configured to expose a portion of thePCB 132 on which the photodiode 140 is mounted.

When the keypad 100 is mounted to a structure, the photodiode 140 may beenclosed by the enclosure 130, the upper, side, and lower walls 134,135, and 136 of the adapter 108, and the structure. The keypad 100 maydefine an aperture through which ambient light may enter the keypad 100and be received by the photodiode 140. For example, as shown the lowerwall 136 of the adapter 108 may define an aperture 144 that extendstherethrough. The photodiode 140 may receive ambient light through theaperture 144, which may enable the ambient light detection circuit tomeasure the light level of the ambient light in the space. As shown, theaperture 144 may be characterized by a width W1 (e.g., approximately0.500″) as shown in FIG. 5. The photodiode 140 may be positioned adistance D1 (e.g., approximately 0.560″) from the aperture 144 (e.g.,from an inner side of the lower wall 136 of the adapter 108) as shown inFIG. 4.

As shown, the faceplate 102 may include a plate shaped body andperimeter walls that extend rearward from the body, including an upperwall 103, a lower wall 105, and opposed side walls 107 that extend fromthe upper wall 103 to the lower wall 105. The upper, side, and lowerwalls 103, 105, and 107 of the faceplate 102 may define an outerperimeter of the faceplate 102 that extends beyond the upper, side, andlower walls 134, 135, and 136 of the adapter 108 such that the aperture144 is hidden from view when the faceplate 102 is attached to theadapter 108 and the keypad 100 is mounted to a structure. Stateddifferently, the faceplate 102 may be wider than the adapter 108 in alateral direction, and may be longer than the adapter 108 in alongitudinal direction so as to hide the aperture 144 from the view of auser when the keypad 100 is mounted to a structure. Locating theaperture 144 in the lower wall 136 of the adapter 108 may prevent therecess 142 from collecting dust that might hinder operation of thephotodiode 140. For example, if the aperture 144 were located in theupper wall 134 of the adapter 108, dust may fall through the aperture144 and collect in the recess 142, such that the dust blocks ambientlight from being received at the light receiving surface of thephotodiode 140. However, it should be appreciated that the keypad 100 isnot limited to the illustrated respective locations of the photodiode140 and the aperture 144, and furthermore is not limited to theillustrated orientations of the photodiode 140 and the aperture 144relative to each other.

The keypad 100 may include a reflector that may be configured to focusambient light that enters the interior of the keypad 100 through theaperture 144 onto the light receiving surface of the photodiode 140. Forexample, as shown the enclosure 130 may include an integral reflector150 that may be configured to direct ambient light received through theaperture 144 onto the photodiode 140. As shown in FIGS. 5 and 6, forexample, the reflector 150 may define a concave reflective surface 152(e.g., a mirror) for directing and/or focusing ambient light that entersthe keypad 100 through the aperture 144 onto the photodiode 140. Thereflective surface 152 may be configured to operate as a parabolicreflector or may be define a curved surface similar to that of aparabolic reflector. As shown, the reflective surface 152 may extendfrom near the rear surface of the PCB 132 to an upper edge 154 of thereflector 150 that is spaced from the rear surface of the PCB 132. Thereflector 150 may be configured such that the upper edge 154 thereofextends rearward away from the PCB 132 and outward relative to therecess 142 and extends over a portion of the photodiode 140. In thisregard, the reflector 150 may define a canopy that partially enclosesthe photodiode 140, such that the photodiode 140 is positioned partlyunder the upper edge 154 of the reflector (e.g., as shown in FIG. 7).The upper edge 154 of the reflector 150 may define a curved perimeter(e.g., as shown in FIG. 4). As shown in FIG. 5, the reflector 150 may becharacterized by a width W2 (e.g., approximately 0.33″) at a base of thereflector 150 where the enclosure 130 contacts the PCB 132. It should beappreciated that the reflector 150 is not limited to the illustratedgeometry. The enclosure 130, and thus the reflector 150, may be made ofwhite glass-enforced polycarbonate. The reflective surface 152 may bedefined by a coating of shiny material that is applied to the reflector.

It should be appreciated that the keypad 100 is not limited to theillustrated faceplate 102 and adapter 108. For example, the keypad 100may be implemented with a faceplate and adapter having the same ordifferent configurations (e.g., geometries) from those illustrated anddescribed herein. The enclosure 130 may be implemented with alternativeconfigurations of the faceplate and/or adapter. To illustrate, theenclosure 130 may be attached to faceplates having sizes and/or shapesthat are different from the faceplate 102. Such faceplates may beconfigured to attach to respective adapters having sizes and/or shapesthat are different from the adapter 108. Accordingly, the distance D1from the aperture 144 to the photodiode 140 (e.g., as shown in FIG. 4)may vary based upon the particular configurations of the faceplateand/or adapter which the enclosure 130 is implemented with. For example,in some example implementations the distance D1 may be long enough toinhibit proper operation of the photodiode 140, for instance if thephotodiode 140 receives too little ambient light. In such animplementation, the keypad 100 may include a light guide that isconfigured to collect ambient light at the aperture 144 and to guide theambient light to the photodiode 140. To illustrate, an example lightguide may be designed such that an amount of ambient light that isreceived by the photodiode 140 of a first keypad implementation thatincludes a light guide, and wherein the distance D1 has a first value,is approximately the same as the amount of ambient light that isreceived by the photodiode 140 of a second keypad implementation inwhich the distance D1 has a second value that is shorter than the firstvalue, and that does not include a light guide. Stated differently, alight guide may be provided in example implementations of the keypad 100where the distance D1 inhibits desired operation of the photodiode 140.In some example implementations that include a light guide, thereflector 150 may be omitted.

FIGS. 8A and 8B depict another example adapter 200 that may beimplemented in the keypad 100, for example in place of the adapter 108.The adapter 200 may be configured to be attached to a structure, such asa structure within an interior wall of a building. As shown, the adapter200 defines a pair of openings 202 that extend therethrough. The adapter200 may be configured such that the openings 202 align with a structureto which the adapter 200 is to be attached. The adapter 200 may also beconfigured to attach directly to an electrical wallbox. For example, asshown, the keypad 100 may include a pair of mounting tabs 220 that areremovably attachable to the adapter 200. Each mounting tab 220 maydefine a pair of openings 222 that extend therethrough. The adapter 200may define corresponding openings 203 that extend therethrough and thatalign with the openings 222 of the mounting tabs 220. The mounting tabs220 may be attached to the adapter 200 using fasteners, such as screws240 that are disposed into the openings 203 of the adapter 200 anddriven into place in the openings 222 of the mounting tabs 220. Eachmounting tab 220 may define a mounting opening 224 that extendstherethrough. When the mounting tabs 220 are attached to the adapter200, the respective mounting openings 224 may be configured similarly tothe mounting openings 133 of the adapter 108. For example, each mountingtab 220 may be configured such that, when the mounting tab 220 isattached to the adapter 200, the mounting opening 224 aligns with acorresponding mounting hole in an electrical wallbox.

The adapter 200 may be configured such that the faceplate 102 and theadapter 200 may be removably attached to each other. For example, asshown the adapter 200 may define recesses 205. Each recess 205 may beconfigured to receive and engage with a corresponding one of thesnap-fit connectors 137 of the faceplate 102. The adapter 200 may definean opening 206 that extends therethrough and that is configured to atleast partially receive the enclosure 130 when the faceplate 102 isattached to the adapter 200. As shown, the adapter 200 may define anaperture 208 that extends through a lower wall 207 of the adapter 200.The aperture 208 may, for example, be configured similarly to theaperture 144 of the adapter 108. In this regards, the photodiode 140 mayreceive ambient light through the aperture 208, which may enable theambient light detection circuit to measure the light level of theambient light in a space in which the keypad 100 is installed.

As shown, one of the mounting tabs 220, such as a lower mounting tab220, may include a light guide 226 that is configured to guide ambientlight that is received through the aperture 208 into an interior of thekeypad 100, toward the reflector 150 and onto the light detectorcircuit, for instance onto the photodiode 140. The light guide 226 maydefine a lower surface 227 that is configured to be received in theaperture 208 of the adapter 200. As shown, the lower surface 227 may beconfigured as a curved lower surface 227. The light guide 226 may beconfigured such that when the lower mounting tab 220 is attached to theadapter 200, at least a portion of the lower surface 227 extends beyondan outer surface 209 of a lower wall 207 of the adapter 200, but isstill hidden from view behind the faceplate 102. Additionally, the lightguide 226 may be configured such that when the lower mounting tab 220 isattached to the adapter 200, at least a portion of the lower surface 227extends beyond an outer surface of 101 of the lower wall 105 of thefaceplate 102.

Stated more generally, the light guide 226 may be configured such thatthe lower surface 227 protrudes beyond a lower surface of the keypad100. Protrusion of a portion of the light guide 226 beyond a lowersurface of the adapter 200 and/or the faceplate 102 may allow the lightguide 226 to collect ambient light that is received by the portion ofthe lower surface 227 that protrudes beyond the lower wall 207 of theadapter and/or the lower wall 101 of the faceplate 102, in addition toambient light that enters the light guide 226 from below the adapter200. Such a configuration of the light guide 226 may enable the lightdetector circuit to more accurately measure the ambient light in aspace, for instance when the keypad 100 is installed above a darksurface that reflects little light, such a piece of furniture having adark and/or matte finish. As shown, the light guide 226 may furtherdefine a tab 228 that may be configured to be received in the recess 142of the enclosure 130. The tab 228 may operate to guide ambient light tothe reflective surface 152 of the reflector 150.

It should be appreciated that the light guide 226 is not limited to theillustrated configuration. For example, the light guide 226 may bealternatively configured such that the lower surface 227 does notprotrude beyond the lower wall 207 of the adapter 200, for example suchthat the lower surface 227 aligns substantially flush with the outersurface of the lower wall 207 of the adapter 200 when the lower mountingtab 220 is attached to the adapter 200.

The keypad 100 may be configured to adjust the active and inactivesurface illumination intensities L_(SUR1), L_(SUR2) in response to themeasured light level of the ambient light. For example, the keypad 100may be configured to increase the active and inactive surfaceillumination intensities L_(SUR1), L_(SUR2) if the ambient light levelincreases, and to decrease the active and inactive surface illuminationintensities L_(SUR1), L_(SUR2) if the ambient light level decreases.

FIG. 9 is a simplified block diagram that illustrates an example controldevice 300 that may be deployed as, for example, the keypad 100 shown inFIG. 1. The control device 300 may include a control circuit 310, whichmay include one or more of a processor (e.g., a microprocessor), amicrocontroller, a programmable logic device (PLD), a field programmablegate array (FPGA), an application specific integrated circuit (ASIC), orany suitable processing device. The control device 300 may include oneor more actuators 312 (e.g., mechanical tactile switches), which may beactuated in response to actuations of the buttons 104, for example. Thecontrol circuit 310 may be coupled to the actuators 312 for receivinguser inputs.

The control device 300 may further include a communication circuit 314,such as a wired communication circuit or a wireless communicationcircuit (e.g., an RF transmitter coupled to an antenna for transmittingRF signals). The control circuit 310 may be coupled to the communicationcircuit 314 for transmitting digital messages, for example in responseactuations of the actuators. Alternatively, the communication circuit314 may include an RF receiver for receiving RF signals, an RFtransceiver for transmitting and receiving RF signals, or an infrared(IR) transmitter for transmitter IR signals. In addition, the controlcircuit 310 may be configured to receive a digital message including,for example, a selected preset and/or the status of an electrical loadcontrolled by an external load control device. The control device 300may also include a memory 316 communicatively coupled to the controlcircuit 310. The control circuit 310 may be configured to use the memory316 for the storage and/or retrieval of, for example, commands and/orpreset information to transmit in response to actuations of the buttons104. The memory 316 may be implemented as an external integrated circuit(IC) or as an internal circuit of the control circuit 310.

The control device 300 may include a power supply 318 for generating adirect-current (DC) supply voltage V_(CC) for powering the controlcircuit 310, the communication circuit 314, the memory 316, and/or otherlow-voltage circuitry of the control device 300. The power supply 318may be coupled to an alternating-current (AC) power source or anexternal DC power source, for example via electrical connections 319.Alternatively, the control device 300 may comprise an internal powersource (e.g., one or more batteries) in place of or in addition to theelectrical connections 319, for supplying power to the power supply 318.

The control device 300 may further comprise a backlighting circuit 320for illuminating indicia on one or more buttons (e.g., the indicia 120of the buttons 104 of the keypad 100). For example, the backlightingcircuit 320 may comprise four LEDs 322 coupled to respective ports onthe control circuit 310 and to respective resistors 324. The controlcircuit 310 may be configured to individually turn each LED 322 on bypulling the respective port low towards circuit common, such that theLED 322 is coupled between the supply voltage V_(CC) and circuit commonthrough the respective resistor 324. The control circuit 310 may beconfigured to dim the illumination of each LED 322, for instance bypulse width modulating the LED current conducted through each LED 322and adjusting a duty cycle DC_(LED) of the pulse-width modulated LEDcurrent.

While the illustrated control device 300 has one LED 322 forilluminating each of the buttons 104, each LED 322 illustrated in FIG. 9may comprise one or more LEDs coupled in series or parallel. Forexample, each LED 322 in FIG. 9 may comprise four LEDs coupled inseries. To illustrate, the LEDs 322 may comprise white LEDs, for examplepart number LTW-C191DS5-LR, manufactured by LITE-ON. Each of theresistors 324 coupled in series with the respective LEDs 322 may have aresistance sized such that the maximum average magnitude of LED currentmay be approximately 20 mA.

The control circuit 310 may be configured to backlight the buttons 104,such that the indicia 120 of a specific button (e.g., a button havingindicia 120 indicative of a selected preset, herein referred to as “theselected button”) is illuminated to an active surface illuminationintensity L_(SUR1), and the respective indicia 120 of the other buttons104 are illuminated to an inactive surface illumination intensityL_(SUR2) that is less than the active surface illumination intensityL_(SUR1). To illuminate the indicia 120 of one of the buttons 104 to theactive surface illumination intensity L_(SUR1), the control circuit 310may pulse-width modulate the LED current through the LED 322 behind thebutton using a first LED duty cycle DC_(LED1) to cause the respectiveLED 322 to illuminate to a first LED illumination intensity L_(LED1). Toilluminate the indicia 120 of one of the buttons 104 to the inactivesurface illumination intensity L_(SUR2), the control circuit 310 maypulse-width modulate the LED current through the LED 322 behind thebutton 104 using a second LED duty cycle DC_(LED2) to cause therespective LED 322 to illuminate to a second LED illumination intensityL_(LED2), which may be less that the first LED illumination intensityL_(LED1).

The control device 300 may further comprise an ambient light detector330 (e.g., an ambient light detection circuit) for measuring an ambientlight level L_(AMB) in a space (e.g., a room) in which the controldevice 300 is installed. The ambient light detector 330 may generate anambient light detect signal V_(AMB), which may indicate the ambientlight level L_(AMB) and may be received by the control circuit 310. Thecontrol circuit 310 may be configured to adjust the first and second LEDillumination intensities L_(LED1), L_(LED2) in response to the measuredambient light level L_(AMB) as determined from ambient light detectsignal V_(AMB). The control circuit 310 may be configured to increasethe first and second LED illumination intensities L_(LED1), L_(LED2) toincrease the active and inactive surface illumination intensitiesL_(SUR1), L_(SUR2) if the ambient light level increases. The controlcircuit 310 may be configured to decrease the first and second LEDillumination intensities L_(LED1), L_(LED2) to decrease the active andinactive surface illumination intensities L_(SUR1), L_(SUR2) if theambient light level decreases.

The control circuit 310 may be configured to adjust the first and secondLED illumination intensities L_(LED1), L_(LED2) by adjusting the dutycycle D_(CLED) through each of the LEDs 322 behind the respectivebuttons 104. For example, the control circuit 310 may be configured toadjust the first duty cycle D_(CLED1) of the LED current through the LED322 behind the button 104 having the active preset in response to themeasured ambient light level L_(AMB) according an active LED adjustmentcurve DC_(ACTIVE), and to adjust the second duty cycle D_(CLED2) of theLED current through each of the LEDs 322 behind the buttons 104 havingthe inactive presets in response to the measured ambient light levelL_(AMB) according an inactive LED adjustment curve DC_(INACTIVE). Theactive LED adjustment curve DC_(ACTIVE) and the inactive LED adjustmentcurve DC_(INACTIVE) may be stored in the memory 316.

FIGS. 10 and 11 illustrate example active and inactive adjustment curvesDC_(ACTIVE), DC_(INACTIVE), respectively, for adjusting the duty cycleDC_(LED) of the LED current through each of the LEDs 322 in response tothe measured ambient light level L_(AMB). FIG. 10 shows the exampleactive and inactive adjustment curves DC_(ACTIVE) and DC_(INACTIVE) on alinear scale, while FIG. 11 shows the example active and inactiveadjustment curves DC_(ACTIVE) and DC_(INACTIVE) on a logarithmic scale.For example, if the measured ambient light level L_(AMB) isapproximately 500 Lux, the first duty cycle DC_(LED1) of the LED currentthrough the LED 322 behind the button 104 having the active preset maybe controlled to approximately 66%, while the second duty cycleDC_(LED2) of the LED current through each of the LEDs 322 behind thebuttons 104 having the inactive presets may be controlled toapproximately 17%.

The human eye may have a more difficult time discerning contrast in lowambient light levels than in high ambient light levels. Thus, the firstduty cycle DC_(LED1) of the active adjustment curve DC_(ACTIVE) may be,for example, over ten times greater than the second duty cycle DC_(LED2)of the inactive adjustment curve DC_(INACTIVE) near a minimum ambientlight level L_(AMB)-MIN (e.g., approximately 0 Lux) as shown in FIGS. 10and 11. Near a maximum ambient light level L_(AMB-MAX) (e.g.,approximately 1000 Lux), the first duty cycle DC_(LED1) of the activeadjustment curve DC_(ACTIVE) may be, for example, approximately threetimes greater than the second duty cycle DC_(LED2) of the inactiveadjustment curve DC_(INACTIVE).

As shown in FIG. 10, the active and inactive adjustment curvesDC_(ACTIVE) and DC_(INACTIVE) are non-linearly related (e.g., notproportional). The difference between the active and inactive adjustmentcurves DC_(ACTIVE) and DC_(INACTIVE) is non-linear as the ambient lightlevel ranges from the minimum ambient light level L_(AMB-MIN) to themaximum ambient light level L_(AMB-MAX). The values of the active andinactive adjustment curves DC_(ACTIVE) and DC_(INACTIVE) may be chosenso that the button 104 having the indicia 120 of the active preset maybe visually distinguished (e.g., visually brighter) than the buttons 104having the indicia 120 of the inactive presets across a range of typicalambient light levels (e.g., between the minimum ambient light levelL_(AMB-MIN) and the maximum ambient light level L_(AMB-MAX)). The valuesof the active and inactive adjustment curves DC_(ACTIVE) andDC_(INACTIVE) may also be chosen so that the indicia 120 on both thebutton 104 having the indicia 120 of the active preset and the buttons104 having the indicia 120 of the inactive presets may be read across arange of typical ambient light levels (e.g., between the minimum ambientlight level L_(AMB-MIN) and the maximum ambient light levelL_(AMB-MAX)).

FIG. 12 depicts an example backlighting process 400 that may be executedperiodically by a control circuit, such as the control circuit 310, forbacklighting a plurality of buttons of a control device, for instancethe buttons 104 of the keypad 100. At 410, the control circuit 310 maysample the ambient light detect signal V_(AMB), and may determine themeasured ambient light level L_(AMB) using the magnitude of the ambientlight detect signal V_(AMB) at 412.

At 414, the control circuit 310 may set a selected-button number N_(SEL)to be equal to the presently selected button (e.g., the button 104having indicia 120 indicating the active or selected preset or scene).For example, the number N_(SEL) may be one (1) for the top button, two(2) for the second button, three (3) for the third button, and four (4)for the bottom button of the keypad 100 shown in FIG. 1. In other words,if the “Evening” button is the selected button, the control circuit 310will set the number N_(SEL) to three (3) at 414. During the backlightingprocess 400, the control circuit 310 may step through the LEDs 322behind each of the buttons 104 and may determine a correct LEDillumination intensity for each of the buttons 104. The control circuit310 may use a variable n for stepping through the LEDs 322 during thebacklighting process 400. At 416, the control circuit 310 may initializethe variable n to one (1).

At 418, if the variable n is equal to the selected-button number N_(SEL)(e.g., the present button is the selected button), the control circuit310 may determine the first LED duty cycle DC_(LED1) for the nth LEDfrom the active adjustment curve DC_(ACTIVE) (e.g., as shown in FIG. 10)using the measured ambient light level L_(AMB) at 420. The controlcircuit 310 may then pulse-width modulate the LED current conductedthrough the nth LED using the first LED duty cycle D_(CLED1) at 422. Ifthe variable n is not equal to the selected-button number N_(SEL) at418, the control circuit 310 may determine the second LED duty cycleDC_(LED2) for the n^(th) LED from the inactive adjustment curveDC_(INACTIVE) (e.g., as shown in FIG. 10) using the measured ambientlight level L_(AMB) at 424 and may pulse-width modulate the LED currentconducted through the n^(th) LED using the second LED duty cycleDC_(LED2) at 426.

At 428, the control circuit 310 may determine if the variable n is equalto a maximum number N_(MAX) (e.g., the number of buttons 104 on thekeypad 100). If the variable n is not equal to the maximum numberN_(MAX) at 428, the control circuit 310 may increment the variable n byone at 430, and the backlighting process 400 may loop around to controlthe intensity of the next LED 322. If the variable n is equal to themaximum number N_(MAX) at 428, the backlighting process 400 may end.

1. A control device comprising: a button comprising a veneer, the veneerhaving an indicia cut therethrough; a light source that is configured tobacklight the indicia of the veneer; a light detector circuit that isconfigured to measure a light level of ambient light that is externalrelative to the control device; a control circuit that is configured to,responsive to an actuation of the button, cause the light source tobacklight the indicia of the veneer in accordance with the measuredlight level; and an enclosure that houses the light detector circuit,the enclosure including an integral reflector that is configured todirect the ambient light to the light detector circuit.
 2. The controldevice of claim 1, wherein the veneer is attached to a front surface ofthe button.
 3. The control device of claim 1, wherein the veneer ismetallic.
 4. The control device of claim 1, wherein the indicia of theveneer is filled with a translucent or clear material.
 5. The controldevice of claim 1, wherein the control circuit is configured to adjustthe light source in response to a change in the measured light level. 6.The control device of claim 5, wherein the control circuit is configuredto adjust the light source to backlight the indicia at a firstillumination intensity when the button has been selected, and whereinthe control circuit is configured to adjust the light source tobacklight the indicia at a second illumination intensity when the buttonhas not been selected.
 7. The control device of claim 1, wherein thebutton is a first button, the veneer is a second veneer, the indicia isa first indicia, and the light source is a first light source, thecontrol device further comprising: a second button comprising a secondveneer that is attached to a front surface of the second button, thesecond veneer having a second indicia; and a second light source that isconfigured to backlight the second indicia of the second veneer, whereinthe control circuit is configured to, responsive to an actuation of thesecond button, cause the second light source to backlight the secondindicia of the second veneer in accordance with the measured lightlevel.
 8. The control device of claim 7, wherein the control circuit isconfigured to control the first light source at a first illuminationintensity and the second light source at a second illuminationintensity.
 9. The control device of claim 1, wherein the light detectorcircuit comprises: a photodiode; and a printed circuit board on whichthe control circuit and the photodiode are mounted, wherein theenclosure defines a recess that exposes the photodiode.
 10. The controldevice of claim 1, further comprising: a faceplate that defines anopening that extends therethrough and that is configured to at leastpartially receive the button; and an adapter that is configured to bemounted to a structure, the adapter including an outer wall that definesan aperture through which the light detector circuit receives theambient light.
 11. The control device of claim 10, wherein the adapterand the faceplate are configured such that the faceplate is removablyattachable to the adapter.
 12. The control device of claim 10, furthercomprising: a pair of mounting tabs that are configured for removableattachment to the adapter, wherein a first mounting tab of the paircomprises a light guide that is configured to guide the ambient lightfrom the aperture to the light detector circuit.
 13. A control devicecomprising: a button comprising a translucent body and an opaquematerial, the opaque material having an indicia cut therethrough; alight source that is configured to backlight the indicia of the button;a light detector circuit that is configured to measure a light level ofambient light that is external relative to the control device; a controlcircuit that is configured to, responsive to an actuation of the button,cause the light source to backlight the indicia of the button inaccordance with the measured light level; and an enclosure that housesthe light detector circuit, the enclosure including an integralreflector that is configured to direct the ambient light to the lightdetector circuit.
 14. The control device of claim 13, wherein the opaquematerial is adhered to the translucent body.
 15. The control device ofclaim 14, wherein the opaque material is adhered to a front surface ofthe translucent body.
 16. The control device of claim 13, wherein theopaque material is metallic.
 17. The control device of claim 13, whereinthe control circuit is configured to adjust the light source in responseto a change in the measured light level.
 18. The control device of claim17, wherein the control circuit is configured to adjust the light sourceto backlight the indicia at a first illumination intensity when thebutton has been selected, and wherein the control circuit is configuredto adjust the light source to backlight the indicia at a secondillumination intensity when the button has not been selected.
 19. Thecontrol device of claim 13, wherein the button is a first button, thetranslucent body is a first translucent body, the opaque material is afirst opaque material, the indicia is a first indicia, and the lightsource is a first light source, the control device further comprising: asecond button comprising a second translucent body and a second opaquematerial, the second button having a second indicia cut therethrough;and a second light source that is configured to backlight the secondindicia of the second button, wherein the control circuit is configuredto, responsive to an actuation of the second button, cause the secondlight source to backlight the second indicia of the second button inaccordance with the measured light level.
 20. The control device ofclaim 19, wherein the control circuit is configured to control the firstlight source at a first illumination intensity and the second lightsource at a second illumination intensity.